Congolese former rebel leader Bosco Ntaganda on Wednesday again refused to attend his war crimes trial on the seventh day of a hunger strike which is posing a legal dilemma for international judges.

Ntaganda is protesting his treatment in detention and has said he is "ready to die", accusing the International Criminal Court of failing to give him a fair chance to defend himself.

"The situation is not developing for the best," his defence lawyer Stephane Bourgon admitted to the court in The Hague where his trial opened a year ago.

"He has not eaten for seven days. There are no signs that he will resume eating," Bourgon said, adding his client had told him earlier Wednesday "he did not feel well enough to attend".

"And if they come and get me, I will refuse to go," Ntaganda said, according to his lawyer.

Ntaganda, who has been held in the ICC's detention unit in the seaside suburb of Scheveningen since he surrendered in 2013, has also instructed his lawyers to stop acting for him.

There is little precedent in international law courts for this kind of situation.

Judge Robert Fremr warned the court's patience was "very close to the end", adding he believed Ntaganda had voluntarily waived his right to attend the trial.

Ntaganda, once dubbed The Terminator, has denied 18 charges of war crimes and crimes against humanity arising out of savage ethnic attacks carried out in the Democratic Republic of Congo by his rebel Patriotic Forces for the Liberation of Congo (FPLC) in 2002-2003.

In a rambling statement read to the court by Bourgon on Tuesday, Ntaganda took issue with the court's refusal last week to ease restrictions on visitors, saying he was losing hope of seeing his wife and children.

But Fremr insisted his family was not banned from seeing him, and that the restrictions were aimed at protecting witnesses.

A psychiatrist who examined Ntaganda on Wednesday concluded "he is mentally competent to oversee the implications of his decisions," Bourgon said.

But despite speaking again to Ntaganda on Wednesday during a 10-minute break in the trial, Bourgon failed to persuade him to return to court.

His client was "emotionally really confused", Bourgon said, adding he was trying to resolve the situation.

The judges on Tuesday ordered the case should continue in Ntaganda's absence, but in the presence of the defence team.

But Bourgon questioned what would happen next.

"Should we force Mr Ntaganda out of his chair and sit him in the video room?" he asked.

"What happens after this witness? And what happens next week when Mr Ntaganda falls unconscious? What will happen then? We will continue with the trial with Mr Ntaganda unconscious on his bed?"